The present invention relates to the development of vaccines. In particular, the present invention relates to apparatus and methods for developing vaccines using ultrasound technology.
Vaccine research and development has seen an increased level of activity, especially with the recent development of biodefense initiatives. The process of recombinant genetic engineering has provided a potential new approach to creating new and improved vaccines for the treatment of disease. So far, this approach has met with limited success for a variety of reasons, and thus many vaccines are still produced via traditional methodologies.
Most classical vaccines are produced by one of two production methods that create either an inactivated (killed) or attenuated (live) vaccine product.
Inactivated vaccines (flu, cholera, hepatitis A) are produced by killing the disease causing microorganism. A number of different methods of inactivation can be used, including chemicals, irradiation, or heat. These vaccines are considered stable and relatively safe since they cannot revert to the virulent (disease-causing) form. The products often do not require refrigeration, a quality that makes them accessible and desirable to domestic healthcare personnel as well as those in developing countries because they are practical for vaccinating people who are in remote locations or involved in highly mobile activities (such as members of the armed force). However, most inactivated vaccines produce a relatively weak immune response and must be given more than once. A vaccine that requires multiple doses (boosters) may have a limited usefulness, especially in areas where people have limited access to regular healthcare.
The second classical approach to the production of vaccines is an attenuated or live vaccine (measles, mumps, rubella). The disease-causing organism is grown under special laboratory conditions that cause it to loose its virulence or disease causing properties. Products prepared in this way require special handling and storage in order to maintain their potency. These products produce both anti-body mediated and cell-mediated immunity and generally they will only require one booster dose.
While live vaccines do have some higher immune response advantages, this method of production has one large drawback. Because the organisms are still living, it is their nature to change or mutate, causing these products to have a remote possibility that the organisms may revert to a virulent form and potentially cause disease; thus, infection may occur either as a result of exposure while handling/processing the vaccine or after administration of the vaccine. Therefore, these vaccines must be carefully tested and monitored. Patients who have compromised immune systems are not usually administered live vaccines.
These two classical approaches to vaccine development and production not only make up the majority of vaccines in use today, but these approaches continue to be used in current vaccine development programs, including the development of vaccines for HIV/AIDS, newly identified variant strains of Hepatitis, etc.
Alliger previously discussed using ultrasound technology to create vaccines in U.S. Pat. No. 5,582,829 (Alliger) and U.S. Pat. No. 6,303,129 (Alliger). Alliger treats substantially viable cells, bacteria or viruses (i.e. those that are intact and capable of functioning) with ultrasound in order to make available antigens capable of inducing an immunogenic and/or therapeutic response. Specifically, the treatment of cells and viruses with ultrasound is intended to deactivate the potentially harmful cells and viruses and to also disperse the antigens present for use as a vaccine without further processing.
Alliger recommends that the procedure is conducted at room temperature while maintaining the temperature of the sample containing the microbe against which a vaccine is developed between zero and 5 degrees Celsius. The minimization of heat is to prevent the denaturing of the antigens. Denaturing these antigens would limit their ability to produce a specific immune response, thus diminishing the potential immunogenic effect of the vaccine. The Alliger method is to deliver ultrasound at a specific frequency, intensity, and duration in order to rupture and destroy the viruses and bacteria within the sample through cavitation, to disperse the available antigens, and to do so without raising the temperature of the viruses or bacteria to a level that would denature the antigens.
Alliger further states that the time must be sufficient to disrupt the viruses or cells so that no virulent cell structure remains to do this, Alliger states that one gram of cultured cells may generally require about 3 minutes of sonication.
As for sonicating the viruses and cells, Alliger delivered ultrasonic waves to the microbe sample through a liquid medium at a frequency of about 20 kHz to about 40 kHz. He stated that above this frequency range cavitation intensity is reduced considerably, even at high power inputs, so that cells or viruses may not be fully disintegrated. Alliger specifically stated that the minimum intensity of the sonic waves should be about 1 watt/sq. cm, and that the preferable intensity level at about 20 kHz is 50 to 175 watts/sq. cm.
Alliger failed to mention the role of using different ultrasound parameters and additional factors such as the volume of the sample/solution containing microorganisms and the geometrical shape of the ultrasound tip and vial/container to be used to achieve the most efficient results in ultrasonic vaccine development. Because of the shortcomings of the classical approaches and Alliger's approach, there is still a need for apparatus and methods that can produce inactivated vaccines that can both produce a stronger immune response and that can produce attenuated microorganisms for vaccine development incapable of reverting back to a virulent strain.